Pure Substances

Mixtures

States of Matter

Physical and Chemical Changes

Everything that has mass and volume is called matter.

Sort your matter!

Cards have the name of a specific kind of matter on the front and what it’s made of on the back

Group your cards according to similarities in the ingredients of each kind of matter

Substances - One Ingredient

Characteristics Include

A substance is matter of a particular kind

Fixed composition

Cannot be separated into simpler substances

by physical methods (physical changes)

Properties do not vary

More specifically…

Substances can be broken down into two groups

Divide your substance group into two groups

Substances can be identified as either an element or compound

Compounds

(made up of molecules)

Can be decomposed into simpler substances by chemical changes

always in a definite ratio

Elements

(made up of individual atoms)

Cannot be decomposed into simpler substances by chemical changes

Pictures of atoms and molecules

Mixtures are two or more substances that are NOT chemically combined.

They are mixed

Components (parts of the mixture) retain their characteristic properties (red color is still red color when mixed)

May be separated into pure substances by physical methods

2 types of mixtures

Take your remaining cards and group them into two groups based on their compositions.

Do not have same composition throughout

Components are distinguishable

Can be separated by physical means

Examples: fruit salad, vegetable soup,

glass of ice water, etc.

Phases in Heterogeneous Mixture

Phases are the individual substances that are combined to make up the mixture.

Can include different states of matter of the same material, ex. Ice & water

Phase Boundary/Interface – where two phases touch

Have the same composition throughout

Components are indistinguishable (Look the same throughout )

can be separated by physical means (distillation, centrifuge, gravimetric filtering, etc.).

• Examples: salt water, solutions, Kool-Aid

• Also called solutions

Solutions are homogenous mixtures

They are easily separated by distillation or evaporation.

Examples: sugar water, salt water

Solutions

Solute – substance being dissolved Solvent – substance doing the dissolving.

Usually water. Concentrated – high solute to solvent ratio Dilute – Low solute to solvent ratio Precipitate – solid that forms from two

solutions.

Solubility – How much solute will dissolve in a certain amount of solvent. See Fig 3.7

Unsaturated – more can be dissolved Saturated – no more will dissolve Supersaturated – more than should be

dissolved at that temperature is dissolved in the solution. Very unstable and will precipitate easily

Colloids are solutions. They can be described as a substance trapped inside another substance. They can be identified by their characteristic scattering of light.

For example: air trapped inside the fat molecules in whipped cream.

•Solids•Liquids•Gases•Plasma•Others

Solids, Liquids, Gases

•Have a definite shape

•Have a definite volume particles are packed tightly together

•Almost incompressible

•Expand only slightly when heated

•Can flow

•Takes the shape of its container

•Has a fixed volume

•Almost incompressible

•Expand when heated

•Particles are far apart

•Take the shape and size of their container

•Expand to fill any space

•Are easily compressed

What is the difference between a gas and a vapor?

The term gas is used for substances that are in a gaseous state at room temperature.

The term vapor is used for describing the gaseous state of a substance that is usually a solid or liquid at room temperature.

Physical properties are those that we can determine without changing the identity of the substance we are studying.

Melting point Boiling point Vapor pressure Color State of matter

Density Electrical conductivity Solubility Adsorption to a surface Hardness

Chemical properties describe the way a substance can change or react to form other substances.

Physical and chemical properties may be intensive or extensive.

Intensive properties such as density, color, and boiling point do not depend on the size of the sample of matter and can be used to identify substances.

Extensive properties such as mass and volume do depend on the quantity of the sample.

• When the substance changes state but does not change its chemical composition.

Melting Boiling Freezing Condensing

Dissolving Cutting

•A chemical change occurs when a substance changes into something new.

A new substance has new properties

Reaction with acids Reaction with bases

(alkalis) Reaction with oxygen

(combustion) Ability to act as

oxidizing agent

Ability to act as reducing agent

Reaction with other elements

Decomposition into simpler substances

Corrosion

Signs of a Chemical Change

Formation of a gas - bubbles Color change Precipitate formed Change in heat – hot or cold (not always

definitive) Physical properties of substance change (no

longer soluble, texture changes, etc.)

There is no observable change in the quantity of matter during a chemical reaction or a physical change.

In other words, matter cannot be created nor destroyed. It is just converted from one form to another

On earth we live upon an island of "ordinary" matter. The different states of matter generally found on earth are solid, liquid, and gas. We have learned to work, play, and rest using these familiar states of matter. Sir William Crookes, an English physicist, identified a fourth state of matter, now called plasma, in 1879.

Plasma temperatures and densities range from relatively cool and tenuous (like aurora) to very hot and dense (like the central core of a star). Ordinary solids, liquids, and gases are both electrically neutral and too cool or dense to be in a plasma state.

The word "PLASMA" was first applied to ionized gas by Dr. Irving Langmuir, an American chemist and physicist, in 1929.

(Above)

X-ray view of Sun from Yohkoh, ISAS and NASA

Star formation in the Eagle Nebula

Space Telescope Science Institute

, NASA

(below)

Plasma radiation within the Princeton Tokamak during operation.

Laser plasma interaction during inertial confinement fusion test at the University of Rochester.

                                         

    

Both inertial and magnetic confinement fusion research have focused on confinement and heating processes with dramatic results. The next stage of operating power reactors will produce about 1 GW of power and operate at 120 million degrees Kelvin.

Plasma can be accelerated and steered by electric and magnetic fields which allows it to be controlled and applied. Plasma research is yielding a greater understanding of the universe. It also provides many practical uses: new manufacturing techniques, consumer products, and the prospect of abundant energy.

Products manufacturedusing plasmas impact our daily lives:

EXAMPLES:

•Computer chips and integrated circuits

•Computer hard drives

•Electronics

•Machine tools

•Medical implants and prosthetics

•Audio and video tapes

•Aircraft and automobile engine parts

•Printing on plastic food containers

•Energy-efficient window coatings

•High-efficiency window coatings

•Safe drinking water

•Voice and data communications components

•Anti-scratch and anti-glare coatings on eyeglasses and other optics

•Waste processing

•Coatings and films

•Electronics

•Computer chips and integrated circuits

•Advanced materials (e.g., ceramics)

•High-efficiency lighting

Plasma technologies are important in industries with annual world markets approaching $200 billion

                         

   

Water Purification

SystemsPlasma-based sources can emit intense beams of UV & X ray radiation or electron beams for a variety of environmental applications.

For water sterilization, intense UV emission disables the DNA of microorganisms in the water which then cannot replicate. There is no effect on taste or smell of the water and the technique only takes about 12 seconds.

                  

This plasma-based UV method is effective against all water-born bacteria and viruses. Intense UV water purification systems are especially relevant to the needs of developing countries because they can be made simple to use and have low maintenance, high throughput and low cost. Plasma-based UV water treatment systems use about 20,000 times less energy than boiling water!

Drastically Reduce Landfill Size

Environmental impact:

High-temperature plasmas in arc furnaces can convert, in principle, any combination of materials to a vitrified or glassy substance with separation of molten metal. Substantial recycling is made possible with such furnaces and the highly stable, nonleachable, vitrified material can be used in landfills with essentially no environmental impact.

Electron-beam generated plasma reactors can clean up hazardous chemical waste or enable soil remediation. Such systems are highly efficient and reasonably portable, can treat very low concentrations of toxic substances, and can treat a wide range of substances.

Environmental impact: